Sengupta S M, VanKanegan M, Persinger J, Logie C, Cairns B R, Peterson C L, Bartholomew B
Program in Molecular Biology, Microbiology, and Molecular Biology and Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901-4413, USA.
J Biol Chem. 2001 Apr 20;276(16):12636-44. doi: 10.1074/jbc.m010470200.
Interactions of the yeast chromatin-remodeling complexes SWI/SNF and RSC with nucleosomes were probed using site-specific DNA photoaffinity labeling. 5 S rDNA was engineered with photoreactive nucleotides incorporated at different sites in DNA to scan for the subunits of SWI/SNF in close proximity to DNA when SWI/SNF is bound to the 5 S nucleosome or to the free 5 S rDNA. The Swi2/Snf2 and Snf6 subunits of SWI/SNF were efficiently cross-linked at several positions in the nucleosome, whereas only Snf6 was efficiently cross-linked when SWI/SNF was bound to free DNA. DNA photoaffinity labeling of RSC showed that the Rsc4 subunit is in close proximity to nucleosomal DNA and not when RSC is bound to free DNA. After remodeling, the Swi2/Snf2 and Rsc4 subunits are no longer detected near the nucleosomal DNA and are evidently displaced from the surface of the nucleosome, indicating significant changes in SWI/SNF and RSC contacts with DNA after remodeling.
利用位点特异性DNA光亲和标记技术探究了酵母染色质重塑复合物SWI/SNF和RSC与核小体的相互作用。构建了5S rDNA，在DNA的不同位点掺入光反应性核苷酸，以便在SWI/SNF与5S核小体或游离的5S rDNA结合时，扫描紧邻DNA的SWI/SNF亚基。SWI/SNF的Swi2/Snf2和Snf6亚基在核小体的多个位置被有效交联，而当SWI/SNF与游离DNA结合时，只有Snf6被有效交联。RSC的DNA光亲和标记显示，Rsc4亚基紧邻核小体DNA，而当RSC与游离DNA结合时则不然。重塑后，在核小体DNA附近不再检测到Swi2/Snf2和Rsc4亚基，它们显然从核小体表面移位，这表明重塑后SWI/SNF和RSC与DNA的接触发生了显著变化。
